So I realize that I don't have enough time myself to convert the incubator site's content to markdown even tho there are scripts to automate that process. Instead let me offer a different idea- to keep the existing build system but superimpose the CMS on top of it.
To facilitate this, all that needs to happen is for someone to find a generic way of invoking anakia so it satisfies the command-line interface of https://svn.apache.org/repos/infra/websites/cms/build/build_external.pl (ie builds sources from ./content/ into a specified target dir). By generic, I mean a suitable command-line invocation for the build_external.pl script for the "anakia" type (basically supplying the right @system_args in the script) so that pretty much any site currently using anakia will be able to do the same thing. Hopefully the challenge to produce such @system_args is within the means of this community ;-)- it amounts to 1 line of perl at this point.